Fan shroud and motor assembly comprised thereof

ABSTRACT

This disclosure proposes designs for a fan shroud that dissipates thermal energy from a motor using a single, externally-powered fan design. Examples of the proposed fan shroud allow the cooling fluid to achieve maximum velocity at a position at which the fan shroud exposes the flow to cooler ambient air that surrounds the fan shroud/motor assembly. In this configuration, the high-velocity cooling fluid draws the cooler ambient air towards the surface of the motor, which, in turn, increases the thermal capacity of the moving cooling fluid to dissipate more thermal energy from the motor.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to structures that dissipatethermal energy and, in particular, to embodiments of a fan shroud thatdisperse cooling fluid about a motor, e.g., for use to actuate the pitchof a turbine wind blade.

Motors that operate under prolonged conditions can generate excessiveheat. The high temperatures that result from these conditions can reduceperformance and shorten the overall lifespan of the motor. To avoidthese problems, many motors incorporate one or more fans that move acooling fluid (e.g., air) over the outer surface of the motor to drawoff and disperse thermal energy. These fans may couple with a shroud,which helps direct a majority of the moving fluid towards the outersurface of the motor.

Designs that improve cooling efficiency and/or cooling rates oftenincrease the amount of cooling fluid that comes in proximity to theouter surface of the motor. For example, some designs utilize additionalfans to disperse more fluid into the shroud. Other designs may increasethe size (e.g., flow rate) of the fan to meet cooling requirements anddemands. When changes to the fan are not practical, however, new designsmay introduce changes in the shroud to provide geometry that harnessesthe cooling fluid in a manner that facilitates thermal dissipation.Unfortunately, although each of these design choices afford betterthermal energy control, the improvements to enhance performance may addcosts and complexity to the design that run contrary to productcommercialization and budgetary constraints.

The discussion above is merely provided for general backgroundinformation and is not intended to be used as an aid in determining thescope of the claimed subject matter.

BRIEF DESCRIPTION OF THE INVENTION

This disclosure proposes designs for a fan shroud that dissipatesthermal energy from a motor using a single fan design. Examples of theproposed fan shroud allow the cooling fluid to achieve maximum velocityat a position at which the fan shroud exposes the flow to cooler ambientair that surrounds the fan shroud/motor assembly. In this configuration,the high-velocity cooling fluid draws the cooler ambient air towards thesurface of the motor, which, in turn, increases the thermal capacity ofthe moving cooling fluid to dissipate more thermal energy from themotor.

This disclosure describes, in one embodiment, a fan shroud for a motor.The fan shroud a top element, a first side element, and a front element.The first side element and the front element couple with the top elementat a first end. The first side element terminates at a second end thatis spaced apart from the motor a first side distance to form a firstside gap. The front element has a front contoured edge proximate to andspaced apart from the motor a first front distance to form a front gap.The first side distance is the same has the first front distance.

This disclosure also describes, in one embodiment, a fan shroud for amotor. The fan shroud has a top element and a pair of side elements thatcouple with the top element at a first end and terminate at a second endthat is spaced apart from the motor a first side distance and a secondside distance to form, respectively, a first side gap and a second sidegap. The fan shroud also has a front element that couples with the topelement and has a front contoured edge proximate to and spaced apartfrom the motor a first front distance to form a front gap. The fanshroud further has a back element that couples with the top element andhas a back contoured end proximate to and spaced apart from the motor afirst back distance to form a back gap. In one example, the first sidedistance is the same as at least one of the first front distance and thefirst back distance.

This disclosure further describes, in one embodiment, a motor assemblywith a motor with a central motor axis. The motor assembly includes amotor with a central motor axis. The motor also includes a fan shroudcoupled to the motor. The fan shroud comprises a first side element anda front element. The first side element terminates at a second end thatis spaced apart from the motor a first side distance to form a firstside gap. The front element has a front contoured edge proximate to andspaced apart from the motor a first front distance to form a front gap.The first side distance is the same as the first front distance.

This brief description of the invention is intended only to provide abrief overview of the subject matter disclosed herein according to oneor more illustrative embodiments, and does not serve as a guide tointerpreting the claims or to define or limit the scope of theinvention, which is defined only by the appended claims. This briefdescription is provided to introduce an illustrative selection ofconcepts in a simplified form that are further described below in thedetailed description. This brief description is not intended to identifykey features or essential features of the claimed subject matter, nor isit intended to be used as an aid in determining the scope of the claimedsubject matter. The claimed subject matter is not limited toimplementations that solve any or all disadvantages noted in thebackground.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features of the invention can beunderstood, a detailed description of the invention may be had byreference to certain embodiments, some of which are illustrated in theaccompanying drawings. It is to be noted, however, that the drawingsillustrate only certain embodiments of this invention and are thereforenot to be considered limiting of its scope, for the scope of theinvention encompasses other equally effective embodiments. The drawingsare not necessarily to scale, emphasis generally being placed uponillustrating the features of certain embodiments of the invention. Inthe drawings, like numerals are used to indicate like parts throughoutthe various views. Thus, for further understanding of the invention,reference can be made to the following detailed description, read inconnection with the drawings in which:

FIG. 1 depicts a perspective view of an exemplary embodiment of a fanshroud as part of a motor assembly;

FIG. 2 depicts a perspective view of an exemplary embodiment of a fanshroud;

FIG. 3 depicts a front view of the fan shroud of FIG. 2;

FIG. 4 depicts a perspective view of the fan shroud of FIG. 2 as part ofa motor assembly;

FIG. 5 depicts a front view of the motor assembly of FIG. 4;

FIG. 6 depicts a flow pattern of cooling fluid that can occur on themotor assembly of FIG. 5;

FIG. 7 depicts a side view of the motor assembly of FIG. 4 to illustratethe flow pattern of cooling fluid of FIG. 6; and

FIG. 8 depicts an example of a material blank that can be used to forman exemplary embodiment of a fan shroud.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exemplary embodiment of a fan shroud 100 that canimprove cooling efficiency to maintain the temperature of a motor. Thefan shroud 100 is part of a motor assembly 102. Examples of the motorassembly 102 find use in a variety of applications, namely, to adjustthe position of rotor blades found in wind turbine systems. In theexample of FIG. 1, the motor assembly 102 has a motor 104 with a centralmotor axis 108. One or more fasteners 110 couple the fan shroud 100 tothe motor 104. This configuration mounts a fan 112, which can secure tothe fan shroud 100, in position on the motor 104.

Implementation of the motor assembly 102 as part of a wind turbinesystem often requires the motor 104 to hold the rotor blades in one ormore desired positions. To fulfill this requirement, the wind turbinesystem often maintains power on the motor 104 for extended periods oftime. Energizing the motor 104 in this manner generates heat. Operationof the fan 112 dissipates the heat from the motor assembly 102 byflowing cooling fluid (e.g., air) into the fan shroud 100 and proximatethe motor 104.

As set forth more below, construction of the fan shroud 100 facilitatescooling by improving flow characteristics of the cooling fluid.Embodiments of the fan shroud 100 form gaps with the motor 104 thatallow cooling fluid to exit the shroud 100. In one embodiment, the gapsare sized and configured to prevent formation of vortexes as the coolingfluid disperses from the fan shroud 100. This feature allows the coolingfluid to flow closely to the motor 104, thus increasing dissipation ofthermal energy from the motor 104 during operation. In otherembodiments, the fan shroud 100 has features that allow the coolingfluid to achieve maximum velocity at locations along the motor 104.These embodiments take advantage of the high velocity of the movingcooling fluid to draw additional, cooler fluid from the environmentoutside of the fan shroud 100 into the flowstreams that form about themotor 104. The addition of this cooler fluid expands the thermalcapacity of the cooling fluid to increase the amount of heat that candissipate from the motor 104, e.g., during extended operation of themotor assembly 102.

The fan shroud 100 can embody a unitary or monolithic structure, e.g.,that is formed from sheet metal (e.g., steel, stainless steel, aluminum,etc.). The materials of construction may comprise thermally conductivematerials that can further enhance thermal dissipation. In otherexamples, construction of the fan shroud 100 can incorporate a number ofindividual pieces that secure together using known fasteners (e.g.,screws and bolts) and techniques (e.g., welds).

FIG. 2 illustrates another exemplary embodiment of a fan shroud 200 foruse in a motor assembly 202. The fan shroud 200 has a top element 214and a plurality of side elements (e.g., a first side element 216 and asecond side element 218). The fan shroud 200 also has a front element220 and a back element 222. As also shown in FIG. 2, the top element 214has an aperture 224. The front element 220 and the back element 222 havean edge 226 that, in one configuration, has a contour that matches thecontour and/or shape of the outer profile of the motor 204. Examples ofouter profile can form a circular shape, e.g., wherein the motor 204 hasa generally round and/or cylindrical configuration.

The fan shroud 200 also comprises one or more mounting features (e.g., afirst mounting feature 228 and a second mounting feature 230) thatsecure to one or more of the front element 220 and the back element 222.In one embodiment, the mounting features 228, 230 are found on both thefront element 220 and the back element 222. The mounting features 228,230 can form an L-bracket with a first portion 232 that extends radiallyand a second portion 234 that extends axially, e.g., relative to theaxis of the motor (e.g., central motor axis 108 of FIG. 1). The firstportion 232 can secure with the fan shroud 200, e.g., to one of thefront element 220 and the back element 222. The second portion 234 canhave an opening 236 that can receive a fastener (e.g., fasteners 110 ofFIG. 1) to secure the fan shroud 200 in position on the motor (e.g.,motor 104 of FIG. 1), as shown in the example of FIG. 1 above.

FIG. 3 illustrates a front view of the fan shroud 200 of FIG. 2. The fanshroud 200 has a shroud axis 238 and a centerline 240 that extendsthrough the shroud axis 238. In one example, the shroud axis 238 forms acenter point for the shape that defines the contour of the edge 226. Theside elements 216, 218 secure to the top element 214 at a first end 242and terminate at a second end 244. As shown in FIG. 3, the ends 244 ofthe first side element 216 and the second side element 218 subtend anangle 246 about the shroud axis 238.

In one embodiment, the fan shroud 200 is symmetric about the centerline240, e.g., where the first side element 216 and the second side element218 are positioned an equal distance with respect to the centerline 240.This configuration locates the second end 244 of the first side element216 diametrically opposite of the second end 244 of the second sideelement 218. However, in other configurations, the fan shroud 200 canforgo such symmetry and still promote optimal flow dynamics of thecooling fluid to improve cooling efficiency, as discussed above. To thisend, values for the angle 246 can vary, e.g., greater than and/or lessthan 90° and/or in a range of 100° to 180°. This disclosure contemplatesthat the angle 246 includes reasonable manufacturing tolerancesunderstood by artisans familiar with relevant techniques to manufactureembodiments of the fan shrouds described herein.

The side elements 216, 218 can take a variety of shapes. For example,the side elements 216, 218 can form a plane and/or a planar surface thatextends from the first end 242 to the second end 244 and axially fromthe front element 114 to the back element 116. In other embodiments, theside elements 216, 218 can form a curvilinear surface, e.g., that curvesinward and/or outward relative to the centerline 240 from the first end242 to the second end 244. This curvature can form concave and/or convexfeature in the side elements 216, 218. Selection of the appropriateshape of the side elements 216, 218 can vary as necessary to tune theflow characteristics (e.g., velocity) of the air transiting out of thefan shroud 200, as disclosed herein.

FIGS. 4, 5, 6, and 7 illustrate the fan shroud 200 in position on themotor 204 of the motor assembly 202. In the perspective view of FIG. 4,the shroud axis 238 aligns with the central motor axis 208 of the motor204. The first side element 216 and the second side element 218 formside gaps (e.g., a first side gap 248 and a second side gap 250) wherethe side element 216, 218 is spaced apart from the motor 204 at thesecond end 244. The edge 226 of the front element 220 and the backelement 222 also forms a front gap 252 and a back gap, identifiedgenerally by the numeral 254. The configuration of the gaps 248, 250,252, 254 allow cooling fluid to exit the fan shroud 200, e.g., duringoperation of the fan 212.

FIG. 5 shows a front view of the fan shroud 200 of FIG. 4. As can beseen in FIG. 5, the configuration of the side gaps 248, 250 providespace between the side elements 216, 218 and the motor 204. The amountof space can be defined at the second end 244 by a first side distancebetween the first side element 216 and the motor 204 and a second sidedistance between the second side element 216 and the motor 204. In oneexample, the first side distance and/or the second side distance areaxially constant from the front (e.g., the front element 220) to theback (e.g., the back element 222) of the fan shroud 200. This featuremaintains the space axially along the central axis 208 of the motor 204.The configuration of the front gap 252 and the back gap 254 providespace between the edge 226 of the front element 220 (and the backelement 222 (FIG. 4)) and the motor 204. The amount of space can bedefined by a first front distance between the edge 226 of the frontelement 220 and the motor 204 and a first back distance between the edge226 of the back element 222 and the motor 204. The shape and contour ofthe edge 226 can determine the values of first front distance and thefirst back distance.

Selection of the distances (e.g., the first side distance, the secondside distance, the first front distance, and the first back distance)can determine how the fluid disperses about the motor 204. In oneimplementation, the space formed by the first gap 248, the second gap250, the front gap 252, and the back gap 254 are the same, i.e., thefirst side distance, the second side distance, the first front distance,and the first back distance are the same.

FIGS. 6 and 7 illustrate one exemplary flow pattern that develops usingembodiments of the fan shroud disclosed herein. In FIG. 6, the flowpattern includes a plurality of primary side airstreams (e.g., a firstprimary side airstream 256 and a second primary side airstream 258). Aplurality of peripheral side airstreams (e.g. a first peripheral sideairstream 260 and a second peripheral side airstream 262) can enter theprimary side airstreams 256, 258 near the second end 244 of the sideelements 216, 218. FIG. 7 depicts a side view of the fan shroud 200 ofFIG. 4 to illustrate additional features of the exemplary flow pattern.In FIG. 7, the flow pattern further includes a plurality of primaryfront airstreams 264 and a plurality of primary back airstreams 266.

As shown in FIGS. 6 and 7, the configuration of the fan shroud 200allows cooling fluid to exit the fan shroud 200 via the side, front, andback as the cooling fluid traverses the motor 204. When the distancesare the same (and/or have similar values, the cooling fluid flows evenlyout of the fan shroud 200 via the gaps 248, 250, 252, 254. As discussedabove, this feature allows the cooling fluid to flow close to the motor204 for distances farther away from the fan shroud to improve heatdissipation that cools the motor 204. In one example, the primary sideairstreams 256, 258 exit the fan shroud 200 at a maximum velocity and ata low pressure. These characteristics of the primary side airstreams256, 258 permits cooler fluid (e.g., peripheral side airstreams 260,262) from outside of the fan shroud 200 to mix with the cooling fluid toimprove thermal dissipation during operation of the fan 212. Thisfeature introduces additional cooling fluid in proximity of the surfaceof the motor 204 to achieve optimal heat transfer for a given flow rateand pressure drop without requiring additional fans or other air movingdevices.

FIG. 8 illustrates an example of a material blank 300 that can be usedto form the fan shrouds 100, 200 of FIGS. 1, 2, 3, 4, 5, 6, and 7.Examples of the material blank 300 can embody a square and/or generallyrectangular piece of sheet metal having a material thickness of fromabout 0.5 mm to about 10 mm. As shown in FIG. 8, this material can becut, e.g., laser cut, to form one or more of the features of the fanshrouds contemplated herein. For example, the laser cutting can createan opening 302, one or more radial surfaces (e.g., a first radialsurface 304 and a second radial surface 306), and tabs 308 withpenetrating apertures 310. In one embodiment, the material blank 300 canhave a number of bend lines 312, about which the material of thematerial blank 300 is shaped and formed to form the general shape andcharacteristics of the fan shrouds discussed above.

As used herein, an element or function recited in the singular andproceeded with the word “a” or “an” should be understood as notexcluding plural said elements or functions, unless such exclusion isexplicitly recited. Furthermore, references to “one embodiment” of theclaimed invention should not be interpreted as excluding the existenceof additional embodiments that also incorporate the recited features.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal language of the claims.

What is claimed is:
 1. A fan shroud for a motor, said fan shroudcomprising: a top element, a first side element, and a front element,wherein the first side element and the front element couple with the topelement at a first end, wherein the first side element terminates at asecond end that is spaced apart from the motor a first side distance toform a first side gap, wherein the front element has a front contourededge proximate to and spaced apart from the motor a first front distanceto form a front gap, and wherein the first side distance is the same hasthe first front distance.
 2. The fan shroud of claim 1, furthercomprising a second side element that couples with the top element atthe first end and terminates at the second end, wherein the second sideelement is spaced apart form the motor a second side distance to form asecond side gap, and wherein the second side distance is the same as thefirst side distance.
 3. The fan shroud of claim 1, further comprising aback element that couples with the top element, wherein the back elementhas a back contoured edge that is spaced apart from the motor a firstback distance to form a back gap, and wherein the first back distance isthe same as the first side distance.
 4. The fan shroud of claim 1,wherein the first side element forms a planar surface that extends alongthe shroud axis.
 5. The fan shroud of claim 1, wherein the first sideelement forms a curvilinear surface that extends along the shroud axis.6. The fan shroud of claim 1, wherein the top element has an apertureextending therethrough.
 7. The fan shroud of claim 1, wherein the firstside element and the front element are formed integrally with the topelement.
 8. The fan shroud of claim 1, wherein the first contour edgeterminates proximate to the second end of the first side element and thesecond end of the second side element.
 9. The fan shroud of claim 1,wherein the front element and the back element couple with the firstside element and the second side element.
 10. The fan shroud of claim 1,further comprising one or more mounting features that secure to one ofthe front element and the back element.
 11. A fan shroud for a motor,said fan shroud comprising: a top element; a pair of side elements thatcouple with the top element at a first end and terminate at a second endthat is spaced apart from the motor a first side distance and a secondside distance to form, respectively, a first side gap and a second sidegap; a front element that couples with the top element and has a frontcontoured edge proximate to and spaced apart from the motor a firstfront distance to form a front gap, and a back element that couples withthe top element, the back element has a back contoured edge proximate toand spaced apart from the motor a first back distance to form a backgap, wherein the first side distance is the same as at least one of thefirst front distance and the first back distance.
 12. The fan shroud ofclaim 11, wherein the second side distance is the same as the first sidedistance.
 13. The fan shroud of claim 11, wherein the first backdistance is the same as the first side distance.
 14. The fan shroud ofclaim 11, wherein the first front distance and the first back distanceare the same as the first side distance.
 15. The fan shroud of claim 11,wherein the side elements comprise a planar surface.
 16. The fan shroudof claim 11, wherein the side elements comprise a curvilinear surfacethat curves relative to a centerline.
 17. A motor assembly, comprising:a motor with a central motor axis; and a fan shroud coupled to themotor, the fan shroud comprising a first side element and a frontelement, wherein the first side element terminates at a second end thatis spaced apart from the motor a first side distance to form a firstside gap, wherein the front element has a front contoured edge proximateto and spaced apart from the motor a first front distance to form afront gap, and wherein the first side distance is the same has the firstfront distance.
 18. The motor assembly of claim 17, wherein the fanshroud further comprises a second side element that couples with the topelement at the first end and terminates at the second end, wherein thesecond side element is spaced apart form the motor a second sidedistance to form a second side gap, and wherein the second side distanceis the same as the first side distance.
 19. The motor assembly of claim17, wherein the fan shroud further comprises a back element that coupleswith the top element, wherein the back element has a back contoured edgethat is spaced apart from the motor a first back distance to form a backgap, and wherein the first back distance is the same as the first frontdistance.
 20. The motor assembly of claim 17, further comprising a fandisposed on the fan shroud, wherein the fan shroud has an aperture toallow cooling fluid to flow through the fan shroud.